Circular knitted products with a warp knitted structure are known (Bulgarian Author's Certificate No. 18304), these products being made of stitch wales, connected by means of longitudinal bonds, and a tuft of filling threads being inserted between the said stitch wales. A disadvantage of these circular knitted goods is that each longitudinal bond connects two adjoining stitch wales, which leads to low longitudinal elasticity and a high transverse deformation, as well as to weak cohesion with the core.
A method is known for making these circular knitted goods, wherein after a simultaneous lifting of all knitting needles, to every two needles consecutively is fed one and the same warp yarn inserted by means of an eye needle guide making a circular reciprocating movement immediately above a needle cylinder.
A disadvantage of this method is that by feeding consecutively the yarn to every two, three or more needles, the yarn is subjected to a higher tension leading to high tearability and corresponding downtime during the process and deterioration of the quality.
Another circular knitted product (Bulgarian Author's Certificate No. 32944) is known, wherein the stitch wales around the core are diametrically connected two by two.
A disadvantage of such circular knitted goods is that its warp knitted structure has specified physical and mechanical, technological and color matching parameters, i.e. cross and longitudinal strength, cross and longitudinal elasticity, molulus of longitudinal bending, porosity, cohesion with the core, etc. below those which are desirable. These circular knitted goods have even numbers of stitch wales. A method is known for making the circular knitted goods of Bulgarian Author's Certificate No. 32944, wherein after a simultaneous lifting of all the needles, the warp yarns are fed around the core circularly and reciprocatively as during the circular reciprocating movement of the warp yarns each is knitted with the diametrically opposite yarn.
A disadvantage of this method is that the system of warp yarns is rotated reciprocatively with a constant angle of 180.degree., so that the method is applicable only to a system of even number warp yarns, and as a result only one type of warp knitted structure can be achieved, i.e. the loop bonds must be diametrically situated.